This post is going to try cover everything flexbox, so that once you're done with going through these links you'll have gone from been a novice flexboxer to someone who knows almost everything there is to know about flexboxes & what it's uses are.
A Complete Guide to Flexbox - https://css-tricks.com/snippets/css/a-guide-to-flexbox/
Flexbox CSS in 20 mins - https://www.youtube.com/watch?v=JJSoEo8JSnc
Learn Flexbox in 15 minutes - https://www.youtube.com/watch?v=fYq5PXgSsbE
CSS Flexbox Crash Course - https://www.youtube.com/watch?v=tXIhdp5R7sc
